Relationship Between Fishing Grounds Of Ommastrephes Bartramiand Satellite Altimeter Data In Northwestern Pacific

The neon flying squid (Ommastrephes bartrami) as one of the important economicspecies in the North Pacific Ocean ecosystem, gradually become a traditional fishingobjects in China in recent years, especially the west stock of winter-spring cohort. Withthe sustainable use and development of oceanic fisheries resources, more and moreinternational communities pay more attention on it. Previous studies mostly focused onthe Sea Surface Temperature (SST), Chlorophyll, currents and so on. It was reportedthat Sea Surface Height (SSH) is closely related to water temperature and salinity. SeaSurface Height information, including dynamic current, tides, water masses, eddiesdynamic and so on, which played a special role in the fishing situation analysis. Alongwith the launch of marine environment satellite “Ocean II”, it was helpful to reveal therelationship between fishing grounds and SSH, which would provide a better method tofind the central fishing grounds.In this paper, based on Chinese mainland squid-jigging data from2008to2012(July-December) and Sea Surface Height Anomaly, Eddy Kinetic Energy (EKE) dataderived from satellite remote sensing to study the relationship between them. WithGeography Information System (GIS) and statistical methods to investigate thetime-spatial distribution of neon flying squid and its relationship with marineenvironment factors, the results are as follows:(1) Spatial and temporal distribution of fishing ground of neon flying squidchanged significantly during the fishing season from2008to2012in the NorthwesternPacific Ocean. The main fishing ground shifted from southeast to northwest from Julyto September, the fishing ground located in40oN on July, while in42~44oN from Aprilto October, and after the beginning of October, they migrated to the south. Then the sexual maturity Ommastrephesbartramisouthward accompanied by the Oyashio coldwater.(2) The paper analyzed the weekly, monthly relationship between SSHA andOmmastrephesbartrami fishing ground during July-December from2008to2012in theNorthwestern Pacific Ocean. It was found that the change trend of neon flying squidwas consistent with SSHA from July to August, and after August the change trend wasopposite. It can be seen that the CPUE of Ommastrephesbartramiincreased with SSHAbefore it reached a certain level, and then would reduce. Along the relationship betweenCPUE and SSHA, which showed that the high yield was distributed in the area wherethe value of SSHA was larger than zero.(3) With the analysis of the optimum SSHA in the high yield fishing zone, whichconcluded that the fishing ground mainly concentrated in the area where SSHA=10around. So we could point that squid mainly live in fringe areas, rather than living in theextreme maximum or minimum area.(4) The regression model was established based on the change rate of Eddy KineticEnergy in the Pacific Northwest and CPUE. It was concluded that they have negativecorrelation. And in the year of2008,2009,2011the correlation coefficients amongthem were high, through the significant test results which showed that the relationshipbetween them is extremely significant; while in2010and2012the correlationcoefficient is significantly lower, the reasons may be: a) the cycle of mesoscale eddyusually lasts a few weeks, they may be just located in the stage of the disappear time ofmesoscale eddy when it was2010and2012; b) the mesoscale eddy in the two yearsmaybe more intensitive relative to other years, and the higher speed of eddy wouldcause most fish to escape.(5) Compared the trends of squid CPUE and EKE, we found that the change trendof CPUE was consistent with EKE from October to December, and have an oppositetrend from July to October. It can be seen that the CPUE ofOmmastrephesbartramireduced with EKE before it reached a certain level, and thenwould increase. Through the significant test results which showed that the relationshipbetween them is extremely significant. And on July and August the squid mainlydistributed in the mixture zone of kuroshio Extension and Oyshio area, they were relative to northeast rather than other months; and on September, October, Decemberthey mainly located in the vicinity of the subarctic ocean currents, the northern side ofsubarctic and the eastern side of Oyshio always be the main habitat for squid.(6) Through the establishment of neon flying squid and Eddy Kinetic Energydistribution histogram, we could conclude that from2008to2012the optimal EKE is25~125cm2·s-2; When the EKE between0cm2·s-2and100cm2·s-2the squid was ratherhigh, and if the EKE>900cm2·s-2, the squid would have a low CPUE.(7) Through the statistics of thematic map of SSHA and neon flying squid, wedivided the fishing ground type into four main categories: a) tongue-based type; b)positive-intensive contour type; c) negative intensive contour type; d) loose type; e)borderline type. We could conclude that the tongue-based fisheries most, maybe becauseit was located in the confluence of warm and cold water, and the warm water was sostrong that result the fishing ground extended to north or northeast, so it was easy toform a circular or oval fishing ground near the edge of cold water eddies.